Information medium and information recording/reproduction apparatus

ABSTRACT

An information medium includes a lead in area and a data area capable of recording an arbitrary information signal. The lead in area has a recordable portion where an information signal can be recorded. The recordable portion of the lead in area has an identifier I 1  defining a recording speed applicable when recording an information signal in the data area. This increases accuracy defining the recording speed.

TECHNICAL FIELD

The present invention relates to information media provided with a dataregion capable of recording desired information signals, and informationrecording and reproducing devices for recording and reproducing desiredinformation to and from such information media.

BACKGROUND ART

CD-ROM and DVD-ROM read-only disc-shaped media, and CD-R, CD-RW, DVD-R,DVD-RW, and DVD-RAM recordable disc-shaped media, as storage media forpersonal computers, and devices for recording, recording andreproducing, or recording, erasing, and reproducing these disc-shapedmedia have become widespread.

There has been a shift in interest from read-only disc-shaped media,which are designed to handle only pre-recorded data, to recordabledisc-shaped media that allow users to input and save data. Inparticular, in order to store image data, in recent years much energyhas been poured into developing recordable discs capable of holdinglarge volumes of data. For example, DVD-R, DVD-RW, and DVD-RAM discs(these three are hereinafter referred to as “recordable discs”), whichhave much larger storage capacities than CD-R or CD-RW discs, have beendeveloped and becoming more popular.

On the other hand, it is desirable that recording speeds are increasedin order to record large volumes of information signals to largecapacity recordable discs. High-speed recording technologies have begunto be developed for devices for recording and reproducing, or recording,erasing, and reproducing, recordable discs (hereinafter, these arereferred to as recording devices).

Recording devices must be compatible with a plurality of types ofrecordable discs with different recording capacities. Recording devicesalso must be able to handle a plurality of different recording speeds.With a recording device for DVD-RAM discs, for example, at presentrecording can be carried out at two recording speeds, normal speed anddouble speed. Thus, in conventional DVD-RAM discs, as shown in FIG. 15,identifiers indicating that recording at double speed is possible arerecorded as non-rewritable pits to a pit portion provided in the lead-inregion of the disc substrate. Also, conventional DVD-RAM recordingdevices were configured so that when a new DVD-RAM disc was placed inthe device, the device would read information written in the pit portionto ascertain the recording speed of that disc and carry out recording atthe recording speed that was ascertained.

However, high-speed recording continues to be a high priority forrecording devices, and conventionally there has been a clear demand forrecording speeds of at least triple speed (hereinafter, referred to as“high speed” in this specification). For example, with recordable discscompatible with low speeds such as double speed, for example, asmentioned above, the information on the compatible recording speeds wasrecorded as pits in the pit portion of the lead-in region of the disc,allowing the recording speed to be controlled. However, the followingproblems occurred when using recordable discs capable of not only thenormal recording speed but also high recording speeds of triple andquadruple speed, for example, in addition to double speed.

That is, different recording speeds result in changes in specific andvery important recording conditions of recordable discs, such as theintensity of the light beam that is irradiated onto the informationlayer when a user records desired data and the mode of pulse modulation.Consequently, in the case of a recordable disc that can be recorded at aplurality of different high speeds, when the above conventionaltechnology is adapted without modification, information on the pluralityof recording conditions corresponding to the recording speeds must berecorded as pits in the lead-in region in addition to the identifiersindicating which recording speeds can be handled.

However, with conventional recording devices performing recordingcontrol simply by detecting only the pit portion there was a risk thatfactors such as incorrect detection of the pit portion, for example,would result in insufficient reliability with respect to appropriaterecording. Consequently, to ensure recording reliability, it isnecessary to record identifiers and information on the recordingconditions twice or three times in the lead-in region.

There are also the following problems with respect to the manufacture ofrecordable discs. That is, the pit portion of the lead-in region wasformed in a non-rewritable format on the disc substrate using a stamperhaving a surface configuration that corresponds to pits. Thus,conventionally it was necessary to prepare a dedicated stamper for eachdisc capable of adapting to different recording speeds. Accordingly, thefollowing problem is conceivable. To take an example, if discs capableof recording at high speeds of quadruple speed or more are mainstream,then a sudden increase in demand for recordable discs designed fortriple speed or less would mean that the substrates for recordable discsthat can be recorded at high recording speeds of quadruple speed or morecould not be used as the substrates for recordable discs designed fortriple speed or less. This is because the identifiers that are recordedin the pit portion of substrates for recording discs designed forquadruple speed or more as non-rewritable pits are different from theidentifiers for recordable discs that are triple speed or less.Consequently, in such a case, it would be necessary to remanufacture astamper for forming non-rewritable identifiers for triple speed or lessin the pit portion and to manufacture disc substrates using thisstamper. Therefore, the inability to quickly respond to changes in thedemand for discs is a foreseeable problem.

In the case of phase-change recordable discs such as DVD-RAM discs, at aminimum the data region is phase-changed to an erased state (ordinarilythis is done through crystallization, and thus will be referred to asinitializing crystallization, crystallization, initialization, orinitializing, for example) so that in general users can record desiredinformation. Then, information indicating which recording operation touse with respect to the disc and information on the recording devicescapable of recording to the disc, for example, are recorded in therecordable portion of the lead-in region and the disc is shipped.

With phase-change recordable discs as well, conventionally theidentifiers specifying compatible recording speeds were recorded in thepit portion of the lead-in region. However, there are instances in whicheven though identifiers indicating that the disc can be recorded atquadruple speed or more, for example, are formed in the pit potion ofthe lead-in region of the substrate, some problem in the process forforming the information layer on the substrate results in the disc beingfound to be incompatible with quadruple speed prior to shipping. In suchinstances, even though the disc can be recorded at triple speed or lesswithout problems, the recordable disc that has been produced isdiscarded, and this wastes resources and/or energy.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide an informationmedium that solves the current problems discussed above and aninformation recording and reproducing device for recording andreproducing the information medium.

To achieve the above object, an information medium according to thepresent invention is provided with a lead-in region and a data region inwhich information signals can be recorded, wherein the lead-in regionhas a recordable portion in which information signals can be recorded,and wherein an identifier specifying a recording speed with respect tothe data region is provided in the recordable portion of the lead-inregion.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram describing a configuration of an information mediumaccording to a first embodiment of the present invention.

FIG. 2 is a diagram describing the main components of an example of theconfiguration of the information recording and reproducing device of thepresent invention.

FIG. 3 is a flowchart showing an example of the operation of theinformation recording and reproducing device of the present invention.

FIG. 4 is a diagram describing a configuration of the information mediumaccording to a second embodiment of the present invention.

FIG. 5 is a flowchart showing an example of the operation of theinformation recording and reproducing device of the present invention.

FIG. 6 is a diagram describing another configuration of the informationmedium according to the second embodiment of the present invention.

FIG. 7 is a diagram describing yet another configuration of theinformation medium according to the second embodiment of the presentinvention.

FIG. 8 is a diagram describing a configuration of the information mediumaccording to a third embodiment of the present invention.

FIG. 9 is a diagram describing another configuration of the informationmedium according to the third embodiment of the present invention.

FIG. 10 is a diagram describing a configuration of the informationmedium according to a fourth embodiment of the present invention.

FIG. 11 is a diagram describing another configuration of the informationmedium according to the fourth embodiment of the present invention.

FIG. 12 is a diagram describing yet another configuration of theinformation medium according to the fourth embodiment of the presentinvention.

FIG. 13 is a diagram describing yet another configuration of theinformation medium according to the fourth embodiment of the presentinvention.

FIG. 14 is a diagram describing an example of identifiers that can beadopted in the present invention.

FIG. 15 is a diagram describing the configuration of a conventionalinformation recording medium.

BEST MODE FOR CARRYING OUT THE INVENTION

The information medium of the present invention, as described above, isprovided with a lead-in region and a data region in which an informationsignal can be recorded, in which the lead-in region has a recordableportion in which information signals can be recorded, and in which anidentifier specifying a recording speed with respect to the data regionis provided in the recordable portion of the lead-in region. Theidentifier provided in the recordable portion of the lead-in region ofthe information medium of the present invention can be an identifierthat directly specifies a recording speed per se, as well as anidentifier that indirectly specifies a recording speed in correspondencewith other information specified in another area of the informationmedium or in a memory or the like of the information recording andreproducing device, for example. A conceivable example of the latter isan information medium provided with a pit portion in the lead-in region,in which an identifier specifying a recording speed with respect to thedata region of the information medium is provided in the pit portion andan identifier corresponding to the identifier of the pit portion (forexample, an identifier that indicates whether the identifier of the pitportion is valid or invalid) is provided in the recordable portion ofthe lead-in region.

According to the present invention, since an identifier is recorded inthe recordable portion of the lead-in region, a recording speed that canbe adopted for the information medium can be specified more accuratelythan with conventional information media, in which identifiers wererecorded in a non-rewritable pit portion. Consequently, the precisionwith which the recording speed of the information medium is recognizedcan be increased and the reliability of information signals recorded tothe data region also can be increased.

Also, with respect to the information medium of the present invention,it is preferable that the identifier recorded in the recordable portionof the lead-in region specifies a maximum speed that can be adopted asthe recording speed with respect to the data region. This is because itis not necessary to increase the number of identifiers of the lead-inregion even if the number of recording speeds with which a singleinformation medium is compatible increases.

In the information medium of the present invention, it is preferablethat the lead-in region further includes a pit portion in whichnon-rewritable pits are formed, and that an identifier specifying arecording speed with respect to the data region is also formed in thepit portion as pits. With this configuration, identifiers specifying therecording speed are provided in both the recordable portion and the pitportion of the lead-in region, and thus with a device for carrying outrecording with respect to this information medium, the recording speedcan be detected in duplicate when information signals are recorded.Accordingly, an information medium in which information is recorded tothe data region with increased reliability can be achieved.

In this information medium, the relationship between the recordingspeeds specified by the identifiers recorded in the pit portion and therecordable portion of the lead-in region can be any of the followingconditions (1) to (5).

(1) The identifier recorded in the recordable portion of the lead-inregion and the identifier recorded in the pit portion specify the samerecording speed.

(2) The identifier recorded in the recordable portion of the lead-inregion and the identifier recorded in the pit portion specify differentrecording speeds.

(3) The identifier recorded in the pit portion specifies a plurality ofdifferent recording speeds, and the identifier recorded in therecordable portion of the lead-in region specifies at least one of theplurality of different recording speeds.

(4) The identifier recorded in the pit portion specifies a plurality ofdifferent recording speeds, and the identifier recorded in therecordable portion of the lead-in region specifies a recording speedthat is different from the plurality of different recording speeds.

(5) The identifier recorded in the pit portion specifies a plurality ofdifferent recording speeds, and the recording speed specified by theidentifier of the lead-in region is equal to or less than the fastestrecording speed that is specified by the identifier of the pit portion.

With the configuration of (1) described above, identifiers specifyingthe same recording speed are recorded in the recordable portion of thelead-in region and in the pit portion, increasing the precision withwhich the recording speed is recognized.

With the configuration of (2) described above, identifiers specifyingdifferent recording speeds are recorded in the recordable portion of thelead-in region and in the pit portion, and thus appropriately selectingwhich recording speed to use in the device for carrying out recordingusing this recording medium increases the versatility of the informationmedium.

With the configuration of (3) described above, for example, of theplurality of different recording speeds specified by the identifiersrecorded in the pit portion, it is possible to specify a recording speedthat can be adopted by individual information media by the identifier ofthe recordable portion of the lead-in region. Accordingly, the samestamper for stamping the pits of the pit portion to a substrate can beshared by information media, for example, improving the yield of theinformation media.

With the configuration of (4) described above, different recordingspeeds can be specified in the recordable portion of the lead-in regionand the pit portion, increasing the degree of freedom with which therecording speed is specified.

With the configuration of (5) described above, it is possible toguarantee a recording speed that can be adopted by the informationmedium by the identifier of the lead-in region.

It is also possible for the information medium of the present inventionto have a lead-in region provided with a recordable portion (firstrecordable portion) and a non-rewritable pit portion, and a data regionprovided with a second recordable portion in which can be recorded aninformation signal, wherein a first identifier in which informationspecifying a speed with which to record to the second recordable portionis recorded as pits is provided in the pit portion, and an identifiercorresponding to the first identifier is provided in the firstrecordable portion. A conceivable embodiment of this is a configurationin which a recording speed is specified directly by the firstidentifier, and an identifier that indicates whether the firstidentifier is valid or invalid, for example, is provided in the firstrecordable portion as the identifier corresponding to the firstidentifier.

In the information medium of the present invention, it is preferablethat recording conditions corresponding to a recording speed specifiedby the identifier are recorded and correlated to that identifier.Recording conditions for example are the various conditions that relateto recording information to the data region, and include the lightintensity when recording and the pulse modulation mode. Thisconfiguration allows multiple recording conditions, which are recordedas pits in the control region provided in the pit portion of the lead-inregion, to be confirmed as well, increasing the reliability with whichinformation signals are recorded to the data region.

In the information medium according to the present invention, it ispreferable that the identifier of the recordable portion of the lead-inregion is recorded in a region describing a medium state (also referredto as a disc identification zone) included in the recordable portion.Accordingly, information on the recording speed is provided in additionto information on the information medium itself and the usage record ofdevices for carrying out recording with respect to the informationmedium, increasing the search speed when recording with a recording andreproducing device, and accordingly increasing the reliability withwhich the recording speed is detected as well.

It is preferable that the information medium according to the presentinvention further is provided with a lead-out region, wherein anidentifier that specifies a speed for recording to the data region isrecorded in the lead-out region as well. Since the lead-out region isaccessed less frequently than the lead-in region, there is the advantagethat identifiers recorded in the lead-out region experience littlesignal deterioration.

Moreover, to achieve the foregoing object, an information recording andreproducing device according to the present invention is provided withan optical pickup for irradiating a light onto an information medium torecord and reproduce information signals to and from an informationlayer of the information medium, a support portion for rotatablysupporting the information medium, a motor for rotating the informationmedium supported by the support portion, a rotation control portion forcontrolling rotation of the motor, and a signal processing portion forprocessing information signals that are reproduced from the informationmedium by the optical pickup, wherein when an information medium of thepresent invention is supported by the support portion and the signalprocessing portion confirms the presence of the identifier from theinformation signal reproduced by the optical pickup from the recordableportion of the lead-in region of the information medium, the rotationcontrol portion controls the motor in correspondence with the recordingspeed specified by the identifier.

With this information recording and reproducing device, the number ofrotations of the motor for rotatively driving the information medium ofthe present invention is controlled based on the recording speedspecified by the identifier provided in the recordable portion of thelead-in region of the information medium, thus allowing an appropriaterecording speed when recording information signals to the data region tobe achieved and allowing the reliability of the information recorded tothe data region to be increased.

If the information medium has the above-described configuration inaddition to a pit portion being provided, then with respect to theinformation recording and reproducing device of the present invention itis preferable that this information medium is supported by the supportportion, the optical pickup reproduces information signals from therecordable portion of the lead-in region and the pit portion of theinformation medium, and the signal processing portion ascertains whetherthe identifier can be confirmed in the information signal from therecordable portion and the information signal from the pit portion.

This information recording and reproducing device confirms the presenceof identifiers specifying a recording speed in both the recordableportion of the lead-in region and the pit portion of the informationmedium. Consequently, the degree of freedom in selecting the recordingspeed is increased, and for example there is the added effect that auser can choose freely the quality control of information signals afterthey have been recorded to the data region, for example.

With the above-described information recording and reproducing device,it is preferable that if the signal processing portion recognizes onlyone identifier from the information signal reproduced by the opticalpickup from the recordable portion of the lead-in region of theinformation medium, then the rotation control portion controls the motorso as to correspond to a speed that is equal to or less than therecording speed specified by the identifier. According to thisconfiguration, in addition to the operations and effects of theabove-described information recording and reproducing device, it ispossible to provide an information medium that itself can guarantee thequality of information signals recorded to the data region, and that isinexpensive due to the increased manufacturing yield of the informationmedium.

Also, with respect to the above information recording and reproducingdevice, it is preferable that if the signal processing portion confirmsa plurality of identifiers from the information signal reproduced by theoptical pickup from the recordable portion of the lead-in region of theinformation medium, then the rotation control portion controls the motorso as to correspond to any one of the plurality of recording speedsspecified by the plurality of identifiers, or so as to correspond to arecording speed that is less than the slowest recording speed of theplurality of recording speeds. According to this configuration, inaddition to the operations and effects of the above-describedinformation recording and reproducing device, there is also the addedeffect that the recording speed when recording to the data region can befine tuned and the information recording capability of the informationmedium can be utilized fully.

Also, with respect to the above information recording and reproducingdevice, it is preferable that if the signal processing portion cannotrecognize an identifier from the information signal reproduced by theoptical pickup from the recordable portion of the lead-in region of theinformation medium, then the rotation control portion controls the motorso as to correspond to a recording speed that is equal to or less thanthe slowest speed of the recording speeds specified by the identifierconfirmed from the information signal reproduced from the pit portion.With this configuration, the upper limit value of the recording speed atwhich the quality of the information signals recorded to the data regioncan be ensured can be set, thus allowing the user to carry out recordingto the information medium without worry. It should be noted that aconfiguration in which the recording speed is not limited if anidentifier is not provided also can be selected freely by changing thealgorithm of the information recording and reproducing device. Choosingthis configuration allows the process steps for recording identifiersduring manufacture of the information medium to be eliminated, therebyinhibiting rises in the cost of information media that are compatiblewith all recording speeds.

Embodiments of the present invention are described in further detailbelow.

Among information media that are capable of recording large volumes ofinformation signals, in very specific terms, DVD-RAM discs are specifiedin a standard called the “DVD Specifications for Rewritable Disc,”DVD-RW discs are specified in a standard called the “DVD Specificationsfor Re-recordable Disc,” and DVD-R discs are specified in a standardcalled the “DVD Specifications for Recordable Disc.” According to thesestandards, the recording region of a DVD can be divided generally into adata region in which desired information signals can be recorded to aninformation layer, and a lead-in region in which information requiredfor recording information signals to the data region is recorded.

The lead-in region is made of a pit portion in which predeterminedinformation signals are recorded in advance as pits during fabricationof a substrate on which an information layer is formed, a recordableportion in which predetermined information signals are recorded(written) to the information layer, and a mirror portion made of aportion of the information layer formed on the flat portion of thesubstrate in which information signals are not recorded. The mirrorportion is provided at the boundary between the pit portion and therecordable portion. The pit portion is also known as the pre-pit portionand the embossed portion. In DVD-RAM discs and DVD-RW discs, therecordable portion is also known as the rewritable portion. The pitportion is made of an initial zone, a reference code zone, a bufferzone, and a control data zone. The recordable portion is made of a guardtrack zone, a disc test zone, a drive test zone, a disc identificationzone, and a DMA1 and DMA2.

It should be noted that in an information medium provided with arewritable information layer, predetermined signals are recorded afterthe information layer has been initialized, and thus all informationsignals formed in the recordable portion of the lead-in region are lostwhen initialization is performed again, for example. However, in thecase of recordable discs, users do not initialize the information laterafter the initialization executed by the manufacturer prior to shipping,and thus optical damage does not occur to information recorded in therecordable portion of the lead-in region.

In conventional recordable discs, information on the recording speed atwhich information signals are recorded to the information layer of thedata region (that is, the second recordable portion) is allocated onebyte in the control data zone of the pit portion. This information isconfirmed from the identifier of the pit portion (that is, the firstidentifier) when the optical pickup of an information recording andreproducing device accesses the pit portion. Then, conventionalinformation recording and reproducing devices keep the recording speedwith respect to the recordable disc at a predetermined speed based onthis information by controlling the number of rotations of the motor forrotatively driving the recordable disc using rotation control means.

However, an increase in the recording speed not only results in anincrease in the number of data specifying recording speeds but therecording conditions corresponding to the recording speeds also change.Consequently, to suitably control the recording conditions in theinformation recording and reproducing device, first it is necessary thatinformation specifying the recording speeds of the recordable disc canbe identified accurately. For that reason, it is necessary that therecording speed is identified and confirmed on the recordable disc bythe information recording and reproducing device by (1) increasing thenumber of first identifiers recorded to the pit portion or (2) providingidentification information specifying a recording speed that correspondsto the first identifier in the recordable portion of the lead-in regionas well.

When (1) is adopted, however, it is possible to increase the number ofidentifications because the first identifiers are formed as pits, but itis not possible to change that number after the substrate has beenmanufactured. Consequently, if the disc loses compatibility with any ofthe plurality of different recording speeds specified by the firstidentifiers due to an error of some kind when forming the informationlayer or when initializing a phase-change disc, for example, it becomesnecessary to discard that disc even if it is still compatible with otherrecording speeds, and this wastes resources and energy. Also, with (1),if the user demands suddenly shift, there is no degree of freedom withwhich to respond to those demands. On the other hand, with (2), it ispossible to change the identifiers after the substrate has beenmanufactured, and there is a high degree of freedom with respect to userdemands.

Even if an erasable information layer is provided, as in the case ofDVD-RW and DVD-RAM discs, as was discussed above, general users do notinitialize the information layer after purchasing the recordable disc,and thus optical damage to the information of the recordable portion ofthe lead-in region does not occur. Also, with commercially availablerecording devices, it is not possible to erase information recorded tothe recordable portion of the lead-in region. Thus, the reliability ofthe identifiers recorded to the recordable portion of the lead-in regionalso can be secured.

Recording identifiers to the recordable portion of the lead-in regioncan be carried out using the same recording method as that usedconventionally to record other information to the recordable portion ofthe lead-in region. It should be noted that other informationconventionally recorded to the recordable portion of the lead-in regionis for example the disc identification information, such as writeinhibit flags, present in the region describing the medium state, anddrive information such as the name of the drive manufacturer. Also, aswill be described later, information expressing recording conditionscorresponding to the recording speeds specified by the identifiers canbe recorded in the recordable portion of the lead-in region along withthe identifiers. This information can be recorded using the sameprocedure at that described above. It should be noted that if there isextra space in the region for recording the identifiers or in zoneswithin that region, then it is preferable that recording conditionscorresponding to the recording speeds specified by the identifiers arerecorded in the same region (and more preferably in the same zone) asthe identifiers.

The area within the recordable portion of the lead-in region in whichthe identifiers are recoded is not fixed, but the region (the regiondescribing a medium state) specified as the disc identification regionin the standard, for example, is particularly preferable because it iswhere information on the recordable disc and on the recording andreproducing device for recording the recordable disc is written.

The region describing the medium state is made of three regions, (1) aregion recording disc identification information writing signalsexpressing whether information signals can be recorded to the dataregion, (2) a region recording drive information including the drivemanufacturer name, added information, and drive conditions, and (3) areserve region in which information is not recorded. Of these threeregions, the drive information region records information on theinformation recording and reproducing device, as mentioned above, andthus it is not very preferable as the area in which to writeidentifiers. Consequently, it is preferable that identifiers arerecorded to the disc information region of the region describing themedium state, or to the region that conventionally served as a reserveregion in which nothing was recorded.

The disc information region is accessed every time that the settings forallowing/forbidding recording to the data region are changed, or everytime that information is recorded to the data region, and thus issearched frequently. Identifiers are not searched as frequently as otherinformation recorded in the disc information region. Also, frequentrewriting of the write inhibit flag runs the risk of unnecessarilyrewriting other information recorded in the disc information region aswell. The reason for this is that when the write inhibit flag isrewritten, not just that flag but an entire block is rewritten as well.Consequently, it is preferable that the area in which identifiers arerecorded is a region other than the disc information region (that is,the region that conventionally served as a reserve region in whichnothing was recorded).

A single disc information region has a capacity of 32,768 bytes, and ofthese, only a single header byte is used to write information (writeinhibit flag) indicating whether recording to the data region ispossible, and the rest is unused. In the case of a recordable discwithout a reserve region, it is also possible for the disc informationregion to serve as the area in which identifiers are recorded.

Embodiments of the information medium and the information recording andreproducing device of the present invention are described below withreference to the drawings.

First Embodiment

FIG. 1 schematically shows the configuration of a recordable discprovided with a lead-in region and a data region serving as anembodiment of the information medium according to the present invention.From the perspective of information signals, the region on a recordabledisc is divided into a pit portion and a recordable portion. The pitportion is a non-rewritable region in which pits are formed by a stamperduring manufacture of the recordable disc substrate. The recordableportion is a region in which information signals can be recorded to theinformation layer by irradiating a light beam. The lead-in regionincludes a pit portion and a recordable portion, as shown in FIG. 1. Theentire data region is a recordable portion. However, in some cases, asin DVD-RAM discs, for example, a sector format is adopted in whichaddresses are formed as pits in the header of each sector. Theinformation layer of the recordable portion of the lead-in region andthe information layer in which information signals are recorded to thedata region are made of identical materials and have identicalcompositions. In this specification, the recordable portion of thelead-in region is referred to as the first recordable portion and therecordable portion of the data region (that is, the entire data region)is referred to as the second recordable portion.

As shown in FIG. 1, the recordable disc of this embodiment is providedwith identifiers P₁ and I₁, which indicate that the disc can be recordedat double speed, in its pit portion and first recordable portion,respectively.

The identifier P₁ recorded in the pit portion is stamped as a pit by astamper when the substrate of the recordable disc is formed, whereas theidentifier I₁ in the first recordable portion is recorded to theinformation layer by irradiating a light beam. That is, the recordabledisc shown in FIG. 1 is manufactured by (1) creating a substrateprovided with the identifier P₁ using a stamper, (2) forming on thissubstrate an information layer that can be recorded at double speed andany other necessary layers, (3) initializing the information layer, and(4) recording information expressing which recording operation toperform with respect to the disc and information on recording devicesthat can record to the disc, together with the identifier I₁ specifyingdouble speed, to the recordable portion of the lead-in region (that is,the first recordable portion).

FIG. 2 is a structural diagram that schematically shows the mainportions of the information recording and reproducing device of thisembodiment. The information recording and reproducing device of thisembodiment is for recording and reproducing desired information signalswith respect to the data region of a recordable disc 1 of thisembodiment, and is provided with a motor 2, a rotation control portion3, an optical pickup 4, a laser drive portion 5, a recording speedrecognition portion 6, a waveform setting portion 7, a signal processingportion 8, a feed motor 9, a motor control portion 10, a positiondetector 11, a system control system 12, a guide shaft 13, a laseremission source 14, an objective lens 15, a photodetector 16, and apreamp 17.

The motor 2 is for rotatively driving the recordable disc 1 after it hasbeen placed on a turntable. The rotation control portion 3 controls thenumber of rotations of the motor 2. The optical pickup 4 is for writingand reading signals to and from the information layer of the recordabledisc 1.

The operations of the above-described structural components aredescribed below.

When the recordable disc 1 is placed on the turntable, the systemcontrol system 12 controls the number of rotations of the motor 2 bysending a command for a predetermined number of rotations to therotation control portion 3. At the same time, the system control system12 sends a command to the feed motor control portion 10 to operate thefeed motor 9. The feed motor 9 rotates in accordance with this command,and as a result the optical pickup 4 first moves to the lead-in regionof the recordable disc 1 along the guide shaft 13.

When the optical pickup 4 arrives at the lead-in region, the positiondetector 11 detects this and outputs a signal to the system controlsystem 12. The system control system 12 receives the information thatthe optical pickup 4 has arrived at the lead-in region, and sends acommand via the waveform setting portion 7 to the laser drive portion 5to emit a laser of a predetermined intensity. The laser drive portion 5drives the laser emission source 14 based on this command.

The light beam that is emitted by the laser emission source 14 isirradiated onto the lead-in region of the recordable disc 1 via theobjective lens 15. Then, the light beam is reflected by the lead-inregion and received by the photodetector 16 after passing through theobjective lens 15 a second time, where it is converted to an electricalsignal that corresponds to the intensity of the reflected light. Thiselectrical signal that has been converted is amplified by the preamp 17.The electrical signal amplified by the preamp 17 is input to the signalprocessing portion 8 as a reproduction signal from the recordable disc1. The signal processing portion 8 receives a command from the systemcontrol system 12, and determines whether the reproduction signalincludes an identifier specifying the recording speed. If thereproduction signal includes such an identifier, then it is sent to therecording speed recognition portion 6.

At this time, the signal processing portion 8 determines whether thereis an identifier specifying the recording speed in the reproductionsignal that is obtained from the pit portion of the lead-in region andthe reproduction signal that is obtained from the recordable portion ofthe lead-in region (the first recordable portion) (steps S1 and S2 inFIG. 3). Then, the recording speed recognition portion 6 confirms thatthe recording speed specified by identifier of the pit portion matchesthe recording speed specified by the identifier of the first recordableportion (step S3), and information is recorded to the data region(second recordable portion) at the recording speed that is thusconfirmed (step S4).

In step S4, the recording speed recognition portion 6 sends a commandfor controlling the number of rotations of the motor 2 to the rotationcontrol portion 3 in correspondence with the information (recordingspeed) of the identifier sent from the signal processing portion 8. Therotation control portion 3, in accordance with this command, rotativelydrives the motor 2 so that the number of rotations thereof correspondsto the recording speed specified by the identifier. A position commandof the position detector 11 is sent to the system control system 12, andthe system control system 12 sends a signal indicating a number ofrotations of the feed motor 9 to the feed motor control portion 10.Accordingly, the feed motor 9 moves the optical pickup 4 to apredetermined position of the data region (second recordable portion),and desired information signals are recorded to the second recordableportion.

As shown in FIG. 1, the recordable disc 1 of this embodiment is providedwith two identifiers specifying the recording speed, the identifier P₁recorded as pits in the pit portion of the lead-in region and theidentifier I₁ recorded to the information layer of the recordableportion (first recordable portion) of the lead-in region. It should benoted that in the flowchart of FIG. 2 described above, recording wasperformed after confirming that the identifier P₁ and the identifier I₁specify identical recording speeds. However, the algorithm fordetermining the recording speed based on the identifier P₁ of the pitportion and the identifier I₁ of the first recordable portion is notlimited to this example, and it is also possible for the manufacturer ofthe information recording and reproducing device to design the algorithmfreely. For example, it is possible to search for the identifier I₁ ofthe first recordable portion only if for some reason the identifier P₁of the pit portion cannot be found. Other specific examples of thealgorithm for determining the recording speed are described below infurther detail in subsequent embodiments.

In this embodiment, by performing recording after searching for theidentifiers P₁ and I₁ from the lead-in region and the first recordableportion and confirming whether the recording speeds specified by theseidentifiers match one another, the accuracy with which the recordingspeeds is recognized by the recording speed recognition portion 6 isincreased. Moreover, the recording conditions related to the recordingspeeds can be determined more accurately in the system control system12.

Second Embodiment

FIG. 4 schematically shows the configuration of another embodiment ofthe recordable disc according to the present invention. This recordabledisc differs from that of the first embodiment in that the recordingspeed specified by the identifier recorded as pits in the pit portion(in this embodiment, double speed) and the recording speed specified bythe identifier recorded to the first recordable portion (in thisembodiment, triple speed) are different.

That is, the recordable disc shown in FIG. 4 is manufactured by formingan information layer that can be recorded at triple speed, for example,on a substrate in which an identifier specifying double speed isrecorded as pits by a stamper, and initializing the information layer,after which information expressing which recording operation to performwith respect to the disc and information on recording devices that canrecord to the disc, together with an identifier indicates that recordingat triple speed is possible, are recorded to the first recordableportion. In other words, the recordable disc shown in FIG. 4 can recordinformation at a maximum speed of triple speed as long as there are noproblems, for example, when forming the information layer.

An overview of the procedure for recording information to the recordabledisc of this embodiment using the information recording and reproducingdevice configured as shown in FIG. 2 is illustrated in the flowchart ofFIG. 5.

Like the first embodiment, the signal processing portion 8 determineswhether identifiers specifying the recording speed are included in thereproduction signal obtained from the pit portion of the lead-in regionand the reproduction signal obtained from the recordable portion of thelead-in region (first recordable portion) (steps S11 and S12). Then, therecording speed recognition portion 6 compares the recording speedspecified by the identifier of the pit portion and the recording speedspecified by the identifier of the first recordable portion (step S13),and if the recording speeds are identical, information is recorded tothe data region (second recordable portion) at that recording speed(steps S14 and S16). On the other hand, if it is determined in step S13that there is a difference in magnitude between the recording speedspecified by the identifier of the pit portion and the recording speedspecified by the identifier of the first recordable portion, then thesystem control system 12 determines which recording speed to performrecording at in accordance with a predetermined algorithm (step S15),and information is recorded at the recording speed that is determined(step S16).

In the case of the recordable disc shown in FIG. 4, the recording speedspecified by the identifier of the pit portion (double speed) is smallerthan the recording speed specified by the identifier of the firstrecordable portion (triple speed). Consequently, the system controlsystem 12 in step S15 determines the recording speed based on theresults of this comparison, and whether the identifier of the pitportion or the identifier of the first recordable portion is givenpriority, or specifically what control to perform, can be selectedfreely through the algorithm incorporated into the system control system12 (or the recording speed recognition portion 6) of the informationrecording and reproducing device. For example, there are at least threeconceivable possibilities. These are: (1) the recording speed specifiedby the identifier of the first recordable portion (triple speed) ispreferentially adopted; (2) the recording speed specified by theidentifier of the pit portion (double speed) is preferentially adopted;(3) the disc is determined to be defective and recording is interrupted(that is, step S16 is not executed).

It should be noted that the algorithm for (1) described above is basedon the consideration that an information layer that can be recorded at amaximum speed of triple speed has been formed using a substratemanufactured for double speed and thus the identifier of the pit portionspecifies double speed, in practice recording up to triple speed can beguaranteed, and the algorithm for (2) is based on the consideration thateven though recording at triple speed is possible, the substrate wasoriginally manufactured for double speed, and thus the recording speedspecified by the identifier of the pit portion is given priority. Thealgorithm for (3) is based on the consideration that the recording speedcannot be guaranteed because the identifiers of the substrate and theinformation layer do not match one another. Any of these considerationsmay be adopted in accordance with the application, specifications, ordesign philosophy, for example, of the information recording andreproducing device.

FIG. 6 is a schematic configuration diagram for describing anotherpossible configuration of the recordable disc of this embodiment. In theexample shown in FIG. 6, there are two identifiers each in the pitportion and the first recordable portion, these being P₃ and P₄, and I₃and I₄, respectively. The identifier P₃ indicates that recording atdouble speed is possible. The identifier P₄ indicates that recording attriple speed is possible. The identifier I₃ indicates that recording attriple speed is possible. The identifier I₄ indicates that recording atquadruple speed is possible.

In other words, an identifier I₄ specifying a recording speed (quadruplespeed) that is greater than either of the two recording speeds specifiedby the identifiers P₃ and P₄ of the pit portion (double speed and triplespeed) is recorded in the first recordable portion.

This recordable disc is a disc in which an information layer that can berecorded at triple speed and an information layer that can be recordedat quadruple speed, for example, are formed on a substrate in whichidentifiers P₃ and P₄ specifying double speed and triple speed arerecorded in the pit portion by stamping, and these information layersare initialized, after which identifiers indicating that recording attriple speed and quadruple speed is possible are recorded in the firstrecordable portion. Thus, it is possible to manufacture a recordabledisc that can be recorded at triple speed and quadruple speed using asubstrate for manufacturing a recordable disc compatible with doublespeed and triple speed.

In the case of the recordable disc shown in FIG. 6 as well, whether toperform recording at a recording speed specified by an identifier of thepit portion (double speed or triple speed) or a recording speedspecified by an identifier of the first recordable portion (triple speedor quadruple speed) can be determined by the recording speed recognitionportion 6 or the system control system 12 using the same predeterminedalgorithms as those described with respect to step S15 of FIG. 5.

FIG. 7 is a schematic configuration diagram for describing yet anotherpossible configuration of the recordable disc of this embodiment. Therecordable disc shown in FIG. 7 has a plurality of identifiers in boththe pit portion and in the first recordable portion. The number ofidentifiers in the pit portion (in this embodiment, four identifiers P₅to P₈) and the number of identifiers in the first recordable portion (inthis embodiment, two identifiers I₅ and I₆) are different. Also, themaximum recording speed specified by an identifier of the pit portion(in this embodiment, ×5 speed specified by P₈) is larger than themaximum speed specified by an identifier of the first recordable portion(in this embodiment, quadruple speed specified by I₆).

In this way, if the number of identifiers of the pit portion and thenumber of identifiers of the first recordable portion is different, thenthe recording speed recognition portion 6 or the system control system12 of the information recording and reproducing device, when determiningthe recording speed, can use an algorithm that determines the recordingspeed taking into account not only the results of comparing themagnitude of the recording speeds specified by the identifiers of thepit portion and the identifiers of the first recordable portion, butalso the results of a comparison of the number of identifiers of the pitportion and the number of identifiers of the first recordable portion.Also, which of the above-described algorithms (1) to (3) is adopted canbe determined freely by the manufacturer of the recording andreproducing device in accordance with the difference in magnitude of therecording speeds specified by the identifiers of the pit portion and therecording speeds specified by the identifiers of the first recordableportion.

It should be noted that an information recording and reproducing devicethat, like in this embodiment, compares (1) the difference in magnitudeof the recording speeds specified by the identifiers of the pit portionand the recording speeds specified by the identifiers of the firstrecordable portion, and/or (2) the difference in number of identifiersof the pit portion and the number of identifiers of the first recordableportion, increases the degree of reliability with which the recordingspeed is set. Also, it becomes possible to identify defects inrecordable discs, for example, and thus the reliability of recordablediscs and the information recording and reproducing device can beincreased.

Also, as shown in FIG. 6 and FIG. 7, if a plurality of identifiers areprovided in both the pit portion and the first recordable portion, thenwhether to adopt as the recordable speed only a recording speedspecified by an identifier or whether to adopt recording speeds that arebelow the lowest recording speed specified by any of the plurality ofidentifiers as well, can be determined suitably by an algorithm of thesystem control system 12 (or the recording speed recognition portion 6).For example, in the former case, if there are identifiers specifyingtriple speed and quadruple speed, then it is determined that therecordable disc can be recorded to only at triple speed or quadruplespeed. On the other hand, in the latter case, the recordable disc ofFIG. 6 is determined to be recordable at single speed or double speed inaddition to triple speed or quadruple speed.

Third Embodiment

FIG. 8 is a schematic configuration diagram showing yet another possibleconfiguration of the recordable disc of the present invention. With thisrecordable disc, there are no identifiers specifying a recording speedin the pit portion and there is a single identifier I₇ (in thisembodiment, triple speed) in the first recordable portion only.

With the information recording and reproducing device configured asshown in FIG. 2, when recording information to this recordable disc, therecording speed recognition portion 6 determines that an identifiercannot be confirmed from the reproduction signal obtained from the pitportion, and thus the recording speed specified by the identifier I₇obtained from the reproduction signal obtained from the first recordableportion (in this embodiment, triple speed) is adopted, and informationis recorded to the data region at this recording speed.

It should be noted that with some information recording and reproducingdevices, recording speeds corresponding to various types of informationmedia may be stored in a memory or the like in advance. If the presentinvention is applied to such an information recording and reproducingdevice and a recordable disc such as that shown in FIG. 8 is used, thenit is possible for the recording speed specified by the identifier ofthe first recordable portion and the recording speed stored in thedevice to be compared, and for the recording speed be determined basedon the results of this comparison. In this case, whether to adopt thefaster or the slower of the recording speeds specified by the identifierof the disc and the recording speed stored in the device, or whether tointerrupt the recording operation if they do not match, can be setfreely by an algorithm of the recording speed recognition portion 6 orthe system control system 12 of the information recording andreproducing device.

FIG. 9 is a schematic configuration diagram for describing yet anotherpossible configuration of the recordable disc of this embodiment. Likethe recordable disc of FIG. 8, there is no identifier in the pitportion, and there are two identifiers I₈ and I₉ (in this embodiment,double speed and triple speed) in the recordable portion (the firstrecordable portion) of the lead-in region only.

With the information recording and reproducing device configured asshown in FIG. 2, when recording information to this recordable disc, therecording speed recognition portion 6 determines that an identifiercannot be confirmed from the reproduction signal obtained from the pitportion, and thus a recording speed specified by either the identifierI₈ or I₉ (in this embodiment, double speed or triple speed) obtainedfrom the reproduction signal obtained from the first recordable portionis adopted, and information is recorded to the data region at thatrecording speed.

It should be noted that as described above, if this recordable disc isused with an information recording and reproducing device in whichrecording speeds corresponding to the recording medium type are storedin a memory or the like in advance, then it is possible for therecording speeds specified by the identifiers of the first recordableportion and the recording speeds stored in the device in advance to becompared and for the recording speed be determined based on the resultsof this comparison. In this case, which of the recording speedsspecified by the identifier of the disc and the recording speeds storedin the device is adopted can be set freely by an algorithm of therecording speed recognition portion 6 or the system control system 12 ofthe information recording and reproducing device.

The recordable discs shown in FIG. 8 and FIG. 9 do not have identifiersin their pit portion, and thus compared to the configuration describedin the second embodiment there is less reliability with respect to therecording speed at which information signals are recorded to therecordable disc. However, if these recordable discs are used in tandemwith an information recording and reproducing device that determines therecording speed giving priority to identifiers of the first recordableportion over identifiers of the pit portion, then information signalscan be recoded to the data region of these discs at an appropriatespeed. It should be noted that although the recordable discs of thisembodiment are provided with a pit portion in the lead-in region, thepresent invention can also be applied to recordable discs that are notprovided with a pit portion. That is, recordable discs in which theentire lead-in region is a recordable portion also fall within the scopeof the present invention, and can record information signals atappropriate recording speeds.

Fourth Embodiment

FIG. 10 is a schematic configuration diagram showing another possibleconfiguration of the recordable disc of the invention. With respect tothe recordable disc of FIG. 10, two identifiers P₉ and P₁₀ specifyingdouble speed and triple speed, respectively, are provided in the pitportion of the lead-in region, and one identifier I₁₀ specifying triplespeed is provided in the recordable portion of the lead-in region (firstrecordable portion).

When information signals are recorded to the data region (secondrecordable portion) of the recordable disc of this embodiment using theinformation recording and reproducing device configured as shown in FIG.2, whether to allow recording only at triple speed as specified by theidentifier I₁₀ of the first recordable portion, whether conversely todisallow only recording at triple speed, which is specified by theidentifier I₁₀, of the recording speeds specified by the identifiers P₉and P₁₀ of the pit portion (that is, to allow recording at double speedor single speed), whether to allow any of the recording speeds specifiedby the identifiers P₉ and P₁₀ of the pit portion and the identifier I₁₀of the first recordable portion to be adopted (that is, to allowrecording at triple speed or double speed), or whether to allowrecording at any speed equal to or less than the recording speedspecified by the identifier I₁₀ of the first recordable portion (thatis, triple speed, double speed, or single speed), can be selected freelyby a predetermined algorithm of the system control system 12 (or therecording speed recognition portion 6). Alternatively, which algorithmto adopt can be chosen to conform to standard norms.

It should be noted that in FIG. 10, the identifier I₁₀ of the recordableportion of the lead-in region (first recordable portion) specifies thesame recording speed as the identifier P₁₀ of the pit portion (in thisexample, triple speed). However, if the identifier of the pit portionspecifies a recording speed, then it is sufficient for the identifier ofthe first recordable portion to be “an identifier that corresponds tothe identifier of the pit portion,” and is not limited to specifying arecording speed per se. For example, the present invention also includesa configuration in which the identifier of the first recordable portiondoes not specify a recording speed per se but rather indicates thevalidity or the invalidity of the identifier of the pit portion. To takea specific example, a conceivable configuration for the recordable discof FIG. 10 would be to make the identifier I₁₀ of the first recordableportion serve as a flag that indicates that the identifier P₁₀ isinvalid rather than specify a recording speed. That is, if theidentifier I₁₀ is a value of 0 (or if there is no identifier in thefirst recordable portion), then recording is possible at double speedand triple speed, and if the identifier I₁₀ is a value of 1, then theidentifier P₁₀ is made invalid (that is, recording at triple speed isnot possible). It should be noted that the information expressed by theidentifier of the first recordable portion and what that informationmeans are of course not limited to this specific example.

FIG. 11 is a schematic configuration diagram for describing anotherpossible configuration of the recordable disc of this embodiment. Therecordable disc of FIG. 11, like the recordable disc of FIG. 10, isprovided with two identifiers P₉ and P₁₀ specifying double speed andtriple speed, respectively, in the pit portion of its lead-in region,and is provided with a single identifier I₁₁ specifying double speed inthe recordable portion of its lead-in region (the first recordableportion).

When information signals are recorded to the data region of therecordable disc of FIG. 11 using the information recording andreproducing device configured as shown in FIG. 2, whether to allowrecording only at double speed as specified by the identifier I₁₁ of thefirst recordable portion, whether conversely to disallow only recordingat double speed, which is specified by the identifier I₁₁, of therecording speeds specified by the identifiers P₉ and P₁₀ of the pitportion (that is, to allow recording at triple speed or single speed),whether to allow any of the recording speeds specified by theidentifiers P₉ and P₁₀ of the pit portion and the identifier I₁₁ of thefirst recordable portion to be adopted (that is, to allow recording attriple speed or double speed), or whether to allow recording at anyspeed equal to or less than the recording speed specified by theidentifier I₁₁ of the first recordable portion (that is, double speed orsingle speed), can be set freely by a predetermined algorithm of thesystem control system 12 (or the recording speed recognition portion 6).

It should be noted that in FIG. 11, the identifier I₁₁ of the recordableportion of the lead-in region (first recordable portion) specifies thesame recording speed as the identifier P₉ of the pit portion (in thisexample, double speed). However, if the identifier of the pit portionspecifies a recording speed, then it is sufficient for the identifier ofthe first recordable portion to be “an identifier that corresponds tothe identifier of the pit portion,” and is not limited to specifying arecording speed per se. For example, a configuration in which theidentifier of the first recordable portion does not specify a recordingspeed per se but rather indicates the validity or the invalidity of theidentifier of the pit portion is also included in the scope of thepresent invention. To take a specific example, a conceivableconfiguration for the recordable disc of FIG. 11 would be to make theidentifier I₁₁ of the first recordable portion serve as a flag thatindicates the validity of the identifiers P₉ and P₁₀ rather thanspecifying a recording speed. In other words, if the identifier I₁₁ is avalue of 0 (or if there is no identifier in the first recordableportion), then both the identifiers P₉ and P₁₀ are valid (recording ispossible at double speed and triple speed), and if the identifier I₁₁ isa value of 1, then only the identifier P₉ is valid (that is, recordingis not possible at triple speed). It should be noted that theinformation expressed by the identifier of the first recordable portionand what that information means are of course not limited to thisspecific example.

FIG. 12 is a schematic configuration diagram showing yet anotherpossible configuration of the recordable disc according to thisembodiment. With respect to this recordable disc, identifiers P₁₁ to P₁₄are provided in the pit portion of the lead-in region, and identifiersI₁₂ and I₁₃ are provided in the recordable portion of the lead-in region(first recordable portion). The identifiers P₁₁ to P₁₄ specify recordingspeeds of double speed to ×5 speed, respectively. The identifiers I₁₂and I₁₃ both specify a recording speed of triple speed.

According to this configuration, recordable discs that are compatiblewith any one, or a plurality of, recording speed(s) selected from agroup made of double speed to ×5 speed can be freely fabricated using acommon substrate for recordable discs compatible with double speed to ×5speed. That is, an information layer that is compatible with any onerecording speed selected from the group consisting of double speed to ×5speed (here, triple speed) and other required layers are suitably formedon a substrate in which identifiers P₁₁ to P₁₄ specifying double speedto ×5 speed are recorded as pits by a stamper, and the information layeris initialized, after which identifiers specifying the recording speedthat can be adopted for the information layer that is formed (here,identifiers I₁₂ and I₁₃) are recorded in the first recordable portion.Thus, recording speeds that can be adopted in practice for therecordable discs can be specified by the identifiers of the firstrecordable portion, regardless of the recording speeds specified by theidentifiers of the pit portion. Consequently, for example, even if it isdetermined prior to shipping that the disc cannot accept every recordingspeed specified by the identifiers of the pit portion, it is notnecessary to discard the disc, as was the case conventionally, and thedisc can be used simply by writing at the recording speed that can beaccepted for the information layer (here, triple speed) as recorded inthe first recordable portion. Also, even if there is a sudden increasein demand for recordable discs that are suited for a specific recordingspeed, that demand can be met quickly because a common substrate isused, and this configuration is advantageous from the perspective ofmanufacturing efficiency as well.

If information is to be recorded to this recordable disc using theinformation recording and reproducing device configured as shown in FIG.2, then the recording speed recognition portion 6 confirms that therecording speeds specified by the identifiers I₁₂ and I₁₃ of the firstrecordable portion match one another, and the system control system 12carries out recording and controls corresponding to that recordingspeed. Thus, according to this embodiment, recording a plural number ofidentical identifiers in the first recordable portion increases theredundancy of these identifiers and allows incorrect determination ofthe recording speed due to a weak signal from an identifier of the firstrecordable portion to be prevented, and this increases reliability.Also, reliability can be increased further by adding a procedure forconfirming whether the recording speed specified by the identifiers ofthe first recordable portion matches a recording speed specified by anyone of the plurality of identifiers of the pit portion. It should benoted that in the above description, the identifiers I₁₂ and I₁₃recorded in the first recordable portion specify the same recordingspeed as one of the identifiers P₉ to P₁₄ of the pit portion (here,triple speed indicated by P₁₂). However, it is sufficient for theidentifiers of the first recordable portion to be “an identifier thatcorresponds to the identifier of the pit portion,” and are not limitedto specifying a recording speed per se. For example, a configuration inwhich the identifiers of the first recordable portion indicate thevalidity or the invalidity of the recording speed specified by anidentifier of the pit portion is included also in the scope of thepresent invention. Specifically, the recordable disc of FIG. 12 may havea configuration in which the identifiers I₁₂ and I₁₃ of the firstrecordable portion serve as flags that indicate the validity or theinvalidity of the recording speed specified by any one of theidentifiers P₁₁ to P₁₄ of the pit portion. That is, if the identifiersI₁₂ and I₁₃ are both a value of 0, or if there is no identifier in thefirst recordable portion, then it is possible to allow the disc to berecorded at every recording speed specified by the identifiers P₁₁ toP₁₄ of the pit portion, and if the identifiers I₁₂ and I₁₃ are both avalue of 1, then it is possible for only the recording speed specifiedby the identifier P₁₁ of the pit portion to be made valid (that is, hererecording is not allowed at a recording speed of triple speed orhigher). Alternatively, if both identifiers I₁₂ and I₁₃ of the firstrecordable portion are a value of 1, then it is possible for only therecording speed specified by the identifier P₁₂ of the pit portion to bemade invalid (that is, here, to allow recording at double speed,quadruple speed, and ×5 speed). It should be noted that the informationexpressed by the identifiers of the first recordable portion and whatthat information means are by no means limited to this specific example.

FIG. 13 is a schematic configuration diagram for describing anotherpossible configuration of the recordable disc of this embodiment. Theidentifiers of the pit portion are the same as in the previousconfiguration (FIG. 12) of this embodiment, and therefore they aredenoted using identical reference numerals (P₁₁ to P₁₄). This recordabledisc differs from the preceding one in that there is one identifier(identifier I₁₄) specifying triple speed in the recordable portion ofthe lead-in region (the first recordable portion), and there is anotheridentifier (identifier I₁₅) in the recordable portion of the lead-outregion.

The recordable disc shown in FIG. 13 is preferable because the recordingspeed can be confirmed prior to the start of recording since anidentifier is provided in the lead-out region as well. In other words,if the identifier I₁₄ of the recordable portion of the lead-in regioncannot be recognized, then it is possible to access the lead-out regionand confirm the identifier I₁₅. Thus, even if for some reason theidentifier I₁₄ of the lead-in region cannot be read, it is stillpossible to control the recording speed properly based on the identifierI₁₅ of the lead-out region. Alternatively, both the lead-in region andthe lead-out region can be accessed before the start of recording so asto confirm both the identifier I₁₄ and the identifier I₁₅. The lead-outregion is overwritten less often than the lead-in region, and thus thereis the advantage that identifiers recorded in the lead-out regionexperience less signal deterioration. It should be noted that FIG. 13shows an example in which a single identifier each is provided in therecordable portion of the lead-in region and the recordable portion ofthe lead-out region. However, it is of course possible to provide aplurality of identifiers in these recordable portions.

In the above embodiments, each identifier indicated a single recordingspeed, however, as shown in FIG. 14, when the identifiers are made torepresent a four bit signal, then a single as well as a combination of aplurality of recording speeds can be expressed using a singleidentifier. The use of such identifiers is preferable from thestandpoint that the number of identifiers can be kept from increasingeven if the number of recording speeds that can be adopted by therecordable disc increases.

It should be noted that in the embodiments described above, when aconfiguration is adopted in which the recording conditions (for example,various conditions such as the light intensity when recording, the lightintensity when reproducing, and the pulse modulation mode) correspondingto the recording speeds specified by the identifiers are recordedtogether with the identifiers, then the recording precision of theinformation recording and reproducing device can be improved, and higherquality information signals can be recorded to the data region.

Also, in the above embodiments, identifiers shown as “quadruple speed,”for example, in the drawings indicate that recording is possible up toquadruple speed, but it is also possible for the identifiers to indicatethe minimum speed that cannot be adopted by that particular informationmedium. In this case, if the information medium can be recorded up totriple speed, then the speed specified by the identifier is “quadruplespeed.”

INDUSTRIAL APPLICABILITY

As set forth above, the information media of the present invention areprovided with identifiers specifying the recording speed when recordingdesired information signals to the data region in at least therecordable portion of the lead-in region, allowing the precision withwhich the recording speed of the information medium is confirmed to beincreased. Thus, it is possible to provide information media capable ofrecording high quality information signals. Also, the information mediayield is increased and resources and energy are kept from being wasted,and this allows costs for the information medium to be reduced.Moreover, there is the excellent effect that simply altering the systemcontrol system, for example, of the information recording andreproducing device allows defects in recording discs to be detected.

1. An information medium comprising: a lead-in region and a data regionin which an information signal can be recorded; wherein the lead-inregion has a recordable portion that is re-recordable in whichinformation signals can be optically recorded, wherein an identifierspecifying a recording speed with respect to the data region is providedin the recordable portion of the lead-in region wherein the lead-inregion further comprises a pit portion in which non-rewritable pits areformed, wherein an identifier specifying a recording speed with respectto the data region also is recorded in the pit portion as pits, whereinthe identifier recorded in the pit portion specifies a plurality ofdifferent recording speeds; and wherein the identifier recorded in therecordable portion of the lead-in region specifies at least one of theplurality of different recording speeds.
 2. An information mediumcomprising: a lead-in region and a data region in which an informationsignal can be recorded; wherein the lead-in region has a recordableportion that is re-recordable in which information signals can beoptically recorded, wherein an identifier specifying a recording speedwith respect to the data region is provided in the recordable portion ofthe lead-in region, wherein the lead-in region further comprises a pitportion in which non-rewritable pits are formed, wherein an identifierspecifying a recording speed with respect to the data region also isrecorded in the pit portion as pits, wherein the identifier recorded inthe pit portion specifies a plurality of different recording speeds; andwherein the identifier recorded in the recordable portion of the lead-inregion specifies a different recording speed from the plurality ofdifferent recording speeds.
 3. An information medium comprising: alead-in region and a data region in which an information signal can berecorded; wherein the lead-in region has a recordable portion that isre-recordable in which information signals can be optically recorded,wherein an identifier specifying a recording speed with respect to thedata region is provided in the recordable portion of the lead-in region,wherein the lead-in region further comprises a pit portion in whichnon-rewritable pits are formed, wherein an identifier specifying arecording speed with respect to the data region also is recorded in thepit portion as pits, wherein the identifier recorded in the pit portionspecifies a plurality of different recording speeds; and wherein therecording speed specified by the identifier of the lead-in region isequal to or less than a maximum recording speed specified by theidentifier of the pit portion.
 4. The information medium according toclaim 1, wherein the identifier of the recordable portion of the lead-inregion is recorded in a region describing a medium state included in therecordable portion.
 5. The information medium according to claim 1,further comprising a lead-out region; wherein an identifier that isidentical to the identifier of the recordable portion of the lead-inregion is recorded in the lead-out region as well.
 6. An informationrecording and reproducing device comprising: an optical pickup forirradiating a light onto an information medium to record and reproduceinformation signals to and from an information layer of the informationmedium; a support portion for rotatably supporting the informationmedium; a motor for rotating the information medium supported by thesupport portion; a rotation control portion for controlling rotation ofthe motor; and a signal processing portion for processing informationsignals that are reproduced from the information medium by the opticalpickup; wherein when an information medium according to claim 1 issupported by the support portion and the signal processing portionconfirms the presence of the identifier from the information signalreproduced by the optical pickup from the recordable portion of thelead-in region of the information medium, the rotation control portioncontrols the motor in correspondence with the recording speed specifiedby the identifier, and wherein if the signal processing portion confirmsa plurality of identifiers from the information signal reproduced by theoptical pickup from the recordable portion of the lead-in region of theinformation medium, then the rotation control portion controls the motorso as to correspond to any one of the plurality of recording speedsspecified by the plurality of identifiers, or so as to correspond to arecording speed that is less than the slowest recording speed of theplurality of recording speeds.
 7. An information recording andreproducing device comprising: an optical pickup for irradiating a lightonto an information medium to record and reproduce information signalsto and from an information layer of the information medium; a supportportion for rotatably supporting the information medium; a motor forrotating the information medium supported by the support portion; arotation control portion for controlling rotation of the motor; and asignal processing portion for processing information signals that arereproduced from the information medium by the optical pickup; whereinwhen an information medium according to claim 1 is supported by thesupport portion and the signal processing portion confirms the presenceof the identifier from the information signal reproduced by the opticalpickup from the recordable portion of the lead-in region of theinformation medium, the rotation control portion controls the motor incorrespondence with the recording speed specified by the identifier,wherein the lead-in region of the information medium further comprises apit portion in which non-rewritable pits are formed; wherein anidentifier specifying a recording speed with respect to the data regionis recorded in the pit portion as pits; and wherein the identifier ofthe recordable portion of the lead-in region is an identifier thatcorresponds to the identifier of the pit portion, the optical pickupreproduces information signals from the recordable portion of thelead-in region and the pit portion of the information medium, and thesignal processing portion checks whether the identifier can be confirmedin the information signal from the recordable portion and theinformation signal from the pit portion.
 8. An information recording andreproducing device comprising: an optical pickup for irradiating a lightonto an information medium to record and reproduce information signalsto and from an information layer of the information a support portionfor rotatably supporting the information medium; a motor for rotatingthe information medium supported by the support portion; a rotationcontrol portion for controlling rotation of the motor; and a signalprocessing portion for processing information signals that arereproduced from the information medium by the optical pickup; whereinwhen an information medium according to claim 1 is supported by thesupport portion and the signal processing portion confirms the presenceof the identifier from the information signal reproduced by the opticalpickup from the recordable portion of the lead-in region of theinformation medium, the rotation control portion controls the motor incorrespondence with the recording speed specified by the identifier,wherein if the signal processing portion confirms a plurality ofidentifiers from the information signal reproduced by the optical pickupfrom the recordable portion of the lead-in region of the informationmedium, then the rotation control portion controls the motor so as tocorrespond to any one of the plurality of recording speeds specified bythe plurality of identifiers, or so as to correspond to a recordingspeed that is less than the slowest recording speed of the plurality ofrecording speeds.
 9. The information medium according to claim 2,wherein the identifier of the recordable portion of the lead-in regionis recorded in a region describing a medium state included in therecordable portion.
 10. The information medium according to claim 2,further comprising a lead-out region; wherein an identifier that isidentical to the identifier of the recordable portion of the lead-inregion is recorded in the lead-out region as well.
 11. The informationmedium according to claim 3, wherein the identifier of the recordableportion of the lead-in region is recorded in a region describing amedium state included in the recordable portion.
 12. The informationmedium according to claim 3, further comprising a lead-out region;wherein an identifier that is identical to the identifier of therecordable portion of the lead-in region is recorded in the lead-outregion as well.